1. Field of the Invention
The present invention relates to a system for disposing waste articles and, more particularly, to a system capable of crushing wasted articles such as household electric machines and collecting valuable matters and harmful matters separately.
2. Description of the Related Art
Hitherto, large-size waste articles are used for reclaiming purpose as they are or after suitable treatment such as crushing or burning. Reclamation without any treatment is inconvenient from the viewpoint of efficient use of restricted land area, while burning of such waste articles poses a problem of "warming" of the earth due to generation of carbon dioxide. Furthermore, waste articles are generally rich in vinyl chloride type plastics which, when burnt, generate noxious gases such as chlorine gas and chloride gases. Such gases undesirably damage the furnace in which the waste articles are burnt, resulting in shortened life of the furnace. Furthermore, such gases seriously impair environmental conditions when relieved to the atmospheric air. It is therefore necessary to employ a suitable means which would prevent such gases from being relieved into the air.
Recovery or collection of metals from waste articles rich in metal is broadly conducted as disclosed in Japanese Unexamined Patent Publication No. 50-156754, but no proposal has been made as to collection of the residue, i.e., the matters left after the removal of the metals. Such residue is usually used for reclaiming purpose with or without treatment such as burning, thus posing the aforesaid problems. Methods have been proposed in Japanese Unexamined Patent Publication Nos. 50-108765 and 50-81967 for sorting waste articles, but these proposed methods are directed mainly to sorting metals out of other components. Thus, plastics are handled together with paper and other matters, without being sorted out of other matters.
A simple method for sorting plastics makes use of difference in specific gravity, as disclosed in Japanese Unexamined Patent Publication Nos. 52-151371 and 58-205552. The methods disclosed in these publications are effective when different components of the waste have different values of specific gravity but are ineffective when different components have similar values of specific gravity as are the cases of different types of plastics having similar specific gravity values.
Another sorting method relies upon the difference in melting points. This type of method is considered to be effective in disposing foamed articles made of thermoplastic materials. However, noxious gases are generated during melting when the plastics include vinyl chloride type plastics, resulting in the problems such as damaging of the apparatus and destruction of environmental conditions.
Thus, the known disposing method in which large-size waste articles are used for reclaiming purpose after a volume reduction through crushing and burning poses problems such as warming of the earth due to generation of carbon dioxide and serious damaging of burning furnaces particularly when vinyl chloride type plastics are included.
The method of the type disclosed in Japanese Unexamined Patent Publication No. 50-156754, in which metals are collected and the residues are used for reclamation, cannot satisfactorily meet the demand for efficient use of restricted land area because this method cannot provide sufficient volume reducing effect.
The methods disclosed in Japanese Unexamined Patent Publication Nos. 52-151371 and 58-205552 cannot provide satisfactory sorting effect when the waste contain different components of similar specific gravity values. Sorting according to the specific gravity is not suitable when the waste includes any component which varies specific gravity according to the state, e.g., foamed articles.
Sorting according to difference in melting temperature is rather unsuitable for use in disposal of general waste articles which often contain vinyl chloride type plastics, since such plastics generate noxious gases during melting, resulting in problems such as damaging of the disposal apparatus and destruction of environmental conditions. Furthermore, this method cannot be used in disposing articles formed from thermosetting plastics because such plastics are never decomposed by heating.
Flons (freons) have been broadly used as a foaming agent for forming foamed articles. The use of flon is quite a common practice in the production of foamed thermal insulators because this foaming agent provides high thermal insulation effect. Nowadays, however, the use of flon type foaming agents is strictly limited by regulations in order to preserve ozone layer around the earth. Preservation of ozone layer requires not only limitation in the use of flon type foaming agents but also collection and disposal of flon type foaming agent which have already been confined in foamed articles to be wasted. Known disposal method poses a problem that the flon trapped in foamed articles as the foaming agent is undesirably relieved to the atmospheric air.